diff --git a/cartographer_ros/cartographer_ros/map_builder_bridge.cc b/cartographer_ros/cartographer_ros/map_builder_bridge.cc
index c811692..3fc7aa5 100644
--- a/cartographer_ros/cartographer_ros/map_builder_bridge.cc
+++ b/cartographer_ros/cartographer_ros/map_builder_bridge.cc
@@ -171,6 +171,9 @@ MapBuilderBridge::GetTrajectoryStates() {
 
     const cartographer::mapping::TrajectoryBuilder* const trajectory_builder =
         map_builder_.GetTrajectoryBuilder(trajectory_id);
+    if (trajectory_builder == nullptr) {
+      continue;
+    }
     const cartographer::mapping::TrajectoryBuilder::PoseEstimate pose_estimate =
         trajectory_builder->pose_estimate();
     if (cartographer::common::ToUniversal(pose_estimate.time) < 0) {